Home fitness companies across the country are telling us the same thing ... their products are selling like hotcakes and sales figures are setting records.

Grant Hayes of California Home Fitness Tells TMZ ... they've sold in record numbers over the past 4 days, and the weekend figures were 10 times above normal. We're told the phones are literally ringing off the hook, and it got really crazy Monday after local governments called for gyms to close.

California Home Fitness already hired 3 different delivery crews to meet demand ... and we're told folks are buying everything -- dumbbells, benches, treadmills, bikes, ellipticals, even the equipment that had been collecting dust. Dumbbells have been selling like toilet paper.

The demand is so crazy, CHF tells us they're having inventory issues because the manufacturers are running into issues getting products in from the ports.

Another retailer, New Life Cardio, tells TMZ ... sales are so unbelievable, their 10,000-square-foot retail warehouse, which was full last Sunday, is now half empty. The biggest sellers are treadmills and exercise bikes, and demand is causing them to switch to bi-weekly shipments instead of bi-monthly.

Meanwhile, folks at California Fitness tell us ... weekend sales were 15 times greater than normal, and the hottest items were treadmills, bikes and free weights. Things are so backed up, there's a 2-day delay on deliveries.

Another home gym retailer, Fit 4 Sale, tells us the company says weekend sales were 6 times higher than average ... everything was selling, but mostly dumbbells, benches and bikes. Fit 4 Sale says demand is also delaying deliveries.

And finally, Johnson Fitness & Wellness Store tells TMZ ... sales traffic is getting ridiculous -- non-stop calls and around 5 times more business than usual. Same thing here -- we're told folks are buying free weights, treadmills and ellipticals.